Entire Marshwort

(Nymphoides geminata (R. Br.) Kuntze)

Total Control Pest

Entire Marshwort is a bottom-rooted, aquatic perennial. It is most clearly distinguished from other aquatic plants with floating leaves by its bright yellow, five-lobed, frilly flowers, which are borne above the water margin. The flowers have a 2.5–3.5 centimetre span, and can be observed from November to April, although they only last one day. It grows on sediments ranging from fine gravel and sand to fine organic silt in depths of up to 2.5 metres. It is characterised by persistent regrowth and spread by fragmentation.

Reasons for the Strategy

Entire marshwort floating in water.

Entire Marshwort’s ability to spread rapidly means it poses a significant threat of obstructing water bodies, and to the natural character of streams and lakes in the Tasman-Nelson region. Entire Marshwort will out-compete water lilies and native species.

Entire Marshwort is assessed at “1” on the infestation curve. There are two active sites in ornamental ponds on privately owned land in Tasman District. The low incidence of Entire Marshwort in the Tasman-Nelson region, extensive areas of suitable habitat, and the potential for it to cause significant adverse effects, mean the benefits of total control far outweigh the costs.


To contribute to the eradication of Entire Marshwort by ensuring that all known sites in the Tasman-Nelson region are inspected annually and all live plants are destroyed during the term of the Strategy.

Alternative Measures

The alternative option of “do nothing” or relying on voluntary control will not achieve the objective of eradication, and will result in significant additional costs to the community with respect to lost natural values and the increased cost of control in the future.

Strategy Rule for Entire Marshwort

The occupier shall destroy all adult and juvenile forms of Entire Marshwort on land that they occupy. A breach of Strategy Rule 4.7.5 is an offence under Section 154(r) of the Biosecurity Act 1993.

Biosecurity Act Requirement

No person shall knowingly sell, propagate, breed, release, or commercially display Entire Marshwort, under Sections 52 and 53 of the Act.